Under the microscope: stationary energy storage facilities: From car to grid: Daimler is gradually expanding in the field of stationary energy storage facilities

It's not just on the road that Daimler is helping to bring about an energy turnaround: with its subsidiaries Deutsche ACCUMOTIVE GmbH und Co. KG and Mercedes-Benz Energy GmbH, the company offers efficient battery systems for electric and plug-in vehicles as well as stationary energy storage facilities for industrial applications and households. Daimler is systematically advancing electromobility in a series of innovative projects: as an example, used batteries from electric cars are getting a second lease of life outside of the vehicle as "2nd-use" battery storage devices. In addition to this, a "living spare-parts store" for battery systems destined for the current smart electric drive fleet is helping to stabilise the German power grid. This efficient dual use improves the LCA and the life cycle costs of electromobility.

By becoming involved in the field of stationary energy storage facilities for industrial customers and household applications through its wholly owned subsidiaries Deutsche ACCUMOTIVE GmbH und Co. KG and the recently formed Mercedes-Benz Energy GmbH, Daimler AG is tapping into new growth opportunities and actively helping to bring about an energy turnaround in the non-automotive sector, too.

Deutsche ACCUMOTIVE develops, produces and markets highly complex drive batteries for Mercedes-Benz and smart hybrid and electric vehicles based on lithium-ion technology. Its extensive battery know-how in the automotive sector is now benefiting stationary battery storage facilities as products that have proven themselves over millions of kilometres under the toughest conditions such as heat and cold are also ideal for stationary use.

Within the innovative business model, the recently formed Mercedes-Benz Energy GmbH is now assuming responsibility for development and global marketing of Mercedes-Benz stationary energy storage facilities. This move gives Daimler's activities in the growing market for stationary batteries an even sharper focus. For the stationary storage facility business, this independence means an increase in flexibility. When its comes to approaching customers in particular, there are clear advantages as the customer group for Mercedes-Benz energy storage facilities is far more diversified than the customer group in the automotive sector, ranging from households to large-scale industry.

The first lithium-ion storage facility on an industrial scale is already on the grid and is operated by partner companies The Mobility House AG and GETEC Energie AG. There are numerous possibilities for stationary energy storage facilities as the concept goes way beyond large-scale industrial applications. The business model, developed in collaboration with Daimler Business Innovation, the Daimler think tank for new business ideas, also includes operations in medium-sized businesses such as supermarkets. Here, too, the stationary energy storage facilities can assist at times of peak demand, such as on hot days.

Mercedes-Benz energy storage facilities are also suitable for private use. Daimler AG started supplying these Home energy storage facilities at the end of April 2016. Up to eight battery modules with an energy content of 2.5 kWh each can be combined to produce an energy storage unit with a capacity of up to 20 kWh. Households with their own photovoltaic systems can therefore buffer surplus solar power with virtually no losses. By combining renewable energy sources with a local battery storage unit, private households can increase their self-consumption of generated energy to as much as 65 percent, thereby bringing about their own "private energy revolution".

Reuse of discarded batteries from electric cars

The life cycle of a plug-in or electric vehicle battery does not have to end after its has done its duty in the vehicle as it can be reused for stationary energy storage units. That's because stationary applications are not susceptible to minor power losses, meaning that economical stationary operation is possible for at least ten more years, it is estimated. Reusing the lithium-ion modules in this way almost doubles their economical usage.

The world's largest 2nd-use battery storage facility is currently under construction in Lünen, Westphalia. In Lünen, battery systems from the second generation of smart electric drive vehicles are being incorporated into a stationary storage unit with a total capacity of 13 MWh. A joint venture between partners Daimler AG, The Mobility House AG and GETEC will be taking the stationary storage facility into operation before the end of this year at the REMONDIS SE site and marketing it on the German primary balancing energy market.

Spare-parts store as energy storage unit

Even battery systems that have not yet been used in electric cars and are instead stored as spare parts can double up as energy storage units. Cooperation partners Deutsche ACCUMOTIVE and enercity (Stadtwerke Hannover AG) will start construction work on a new battery storage facility this year. What makes it particularly special is the fact that this is a spare parts storage facility for electromotive battery systems. Around 3000 of the battery modules set aside for the current smart electric drive vehicle fleet are being pooled to create a stationary storage facility at the enercity site in Herrenhausen. With a storage capacity totalling 15 MWh, the installation is one of the largest of its kind in Europe. After completion, the energy storage facility will be marketed on the German primary balancing energy market (PRL).

In this way, the business model makes an important contribution to stabilisation of the power grid and to the economic efficiency of electromobility. In the event of increasing fluctuations in electricity feed-in from renewable energies such as wind and solar energy, such storage units help to ensure optimum setting of a mains frequency that has to be kept constant.